There has hitherto been employed a helical scan tape recorder in which a rotatable magnetic head provided in a rotary head unit has a sliding contact with a magnetic tape which is wound about the perimetrical surface of the rotary head unit and which is run in one or the other direction in order to effect recording and/or reproduction of information signals. With this type of the tape recorder, a tape cassette having a magnetic tape wound across a pair of tape reels rotatably mounted within a cassette unit is employed as a recording medium.
In a tape recorder having a tape cassette and a rotary head unit as a recording medium and as recording and/or reproducing means for information signals, respectively, it has been proposed to cause a rotationally driven magnetic head of the rotary head unit to have a relative sliding contact with a running magnetic tape within the cassette unit in order to effect recording and/or reproduction of information signals.
By utilizing such a design in which the rotary head unit extends into the cassette unit, the tape recorder itself may be reduced in size.
Specifically, the tape cassette as a recording medium is loaded into a position within a recorder main body of the tape recorder. When the tape cassette is loaded in its loaded position, a pair of reel driving shafts provided on the tape recorder side extend into and are engaged by a pair of tape reels of the tape cassette. If one or both of reel driving shafts are rotatably driven, the magnetic tape wound across a pair of tape reels travels from the supply side tape reel towards the takeup side tape reel.
The portion of the magnetic tape wound within the tape cassette which is run across the tape reels is exposed outwardly by means of an opened face of the cassette unit. The magnetic tape is exposed through the front surface side of the cassette unit facing the rotary head unit. When the tape cassette is loaded in position within the tape recorder, the rotary head unit is extended into the tape cassette from the front side of the cassette unit so as to have a sliding contact with the magnetic tape.
Within the tape cassette, a pinch roller is provided at the reverse side of the magnetic tape running across the tape reels which is opposite to the front side thereof facing outwardly of the cassette. The pinch roller is formed of a high frictional coefficient material, such as butyl rubber, and is cylindrically-shaped and rotatably mounted with its outer peripheral surface in sliding contact with the reverse surface of the magnetic tape.
On the other hand, the rotary head unit provided on the tape recorder side is provided with a cylindrically-shaped stationary drum and a rotary drum which is mounted coaxially with the stationary drum and which is rotatably supported with respect to the stationary drum. The magnetic tape is wrapped around the stationary drum and the rotary drum. The magnetic head is mounted on the surface of the rotary drum facing the stationary drum and is slightly protruded from the outer peripheral surface of the rotary drum. By being mounted integrally with the rotary drum, the magnetic head is rotated in unison with the rotary drum.
When the above-described tape cassette is loaded in position within the tape recorder, the rotary head unit is extended into the tape cassette through the opened front surface of the cassette half. With the rotary head unit thus extended into the tape cassette, the magnetic tape running across the tape reels is wrapped over the peripheral surfaces thereof at a predetermined angle in order to achieve relative sliding contact between the magnetic head and the magnetic tape.
When the rotary head unit is partially extended into the inside of the tape cassette loaded in position, the rotary head unit is supported by the tape cassette to be positioned relative to the tape cassette. That is, the rotary head unit is positioned with the tape cassette thus loaded in position as an intrusion reference position.
The rotary head device is provided with a capstan adapted for running the magnetic tape at a constant velocity in cooperation with the pinch roller provided within the tape cassette. The capstan is rotatably mounted at the distal end of a capstan supporting arm which is, in turn, rotatably mounted with respect to the stationary drum. The capstan is moved towards the pinch roller within the tape cassette by being rotated relative to the stationary drum for clamping the magnetic tape in cooperation with the pinch roller. The magnetic tape is run at a constant velocity by the capstan being rotated by rotational driving means, such as a driving motor. As a result of the magnetic tape being run at a constant velocity and the rotary drum of the rotary head unit being rotated, the magnetic tape has a sliding contact with the magnetic head, so that information signals may be recorded on or reproduced from the recording track formed at a fixed angle of inclination relative to the longitudinal direction of the magnetic tape.
Meanwhile, with the above-described tape recorder, when the magnetic tape is run in one direction, a slanted recording track is formed on an upper half-width portion of the magnetic tape, whereas, when the magnetic tape is run in the opposite direction, a slanted recording track is formed on a lower half-width portion of the magnetic tape. that is, by running the magnetic tape in both the forward and reverse directions, information signals may be recorded across the total width of the magnetic tape.
For recording information signals on the upper and lower half width portions of the magnetic tape, it is necessary to reverse the running direction of the magnetic tape. In order to reverse the running direction of the magnetic tape, it is necessary to reverse the surface of the tape cassette mounted in a cassette loading unit within the tape recorder. That is, it is necessary to reverse the loading state of the tape cassette in the cassette loading unit. Consequently, the information signals cannot be recorded on both the upper and lower width portions of the magnetic tape by simply reversing the running direction of the magnetic tape. For reproducing the information signals recorded on the upper and lower width portions of the magnetic tape, it becomes similarly necessary to reverse the loading state of the tape cassette in the cassette loading unit.